Optical add/drop multiplexers (OADMs) are widely used in optical networks. OADMs can be used to provide local termination of traffic and optical cross-connect of multiple optical systems. The main problem in cross-connecting long-haul optical systems include coherent cross-talk (or multi-path interference (MPI)), amplitude equalization and chromatic dispersion. These issues become increasingly problematic in high bit rate applications. Multiple cascaded three-port filters are commonplace, but filter isolation is not absolute and therefore they introduce MPI. The MPI is introduced through a “reflective” express path on which the non-add/drop traffic is routed. Tunable filters are sometimes used but are, in general, unable to be reconfigured without affecting some other traffic on the line other than that being switched.